Optical integrated circuits include devices such as 1×N splitters, switches, wavelength division multiplexers and other like devices which may be deposited on a planar substrate, often referred to as a chip. The devices in the optical integrated circuit are often connected by waveguides. These waveguides are usefully planar waveguides that are fabricated on the surface of the chip. These planar waveguides are fabricated by a variety of techniques using various materials well known to one having ordinary skill in the art. The OIC is achieving more widespread use because it enables a more integrated and reliable structure for optical components. Moreover, the OIC is readily manufacturable with known manufacturing techniques.
The OIC is often connected to an optical fiber array for either short-haul or long-haul transmission via existing infrastructure. As such, it is useful to have an accurate interconnection between the OIC and the optical fiber array.
The accuracy of the interconnection depends greatly upon the alignment between the OIC and the optical fiber array at the interconnection point. As such, accurate optical connectors are used. Moreover, industry standards have resulted in the use of a variety of connectors.
There are basically two alignment techniques used to align the optical waveguides of the OIC to the optical fibers of a fiber array. One alignment technique is via active alignment, where the optical fibers are aligned to the planar waveguides while monitoring the optical transmission of the connection visually or by other active monitoring techniques. While active alignment enables a great deal of accuracy in the optical interconnection, it is a time consuming and labor intensive method. As such, it is not well suited for large-scale manufacturing.
Another alignment technique used to achieve alignment between waveguides of an OIC and an optical fiber array is passive alignment. Passive alignment comprises positioning the optical waveguides of the OIC relative to the optical fiber array without the labor intensive monitoring of the optical transmission of the connection. Passive alignment techniques have gained a great deal of popularity within the optical community because they afford a large-scale and low-cost technique for achieving the desired interconnection. Unfortunately, even though passive alignment techniques have the advantage of low-cost and large-scale manufacturing, the accuracy of the alignment may be less than acceptable.
Accordingly, what is needed is an interconnection structure for connecting waveguides in a passive manner which overcomes the drawbacks of the prior art described above.